Two years after the disaster caused by Russia’s bombing of the Nova Kakhovka Dam in Ukraine, nature has taken over the flooded lands. But this „green lung” could be lost as quickly as it appeared.
At the southern tip of Europe’s largest river island, the land falls prey to a vast and unexpected perspective. From a high and rocky ledge on Hortytsia Island, the view opens to a sea of young willows swaying and mirrored lagoons. Some of the trees are already several meters tall, but this is a young forest. Just a few years ago, everything was underwater here, writes The Guardian.
"This is Velikii Luh – the Great Meadow," says Valerii Babko, a retired history professor and army veteran, standing on the shore of the former reservoir in the village of Malokaterynivka. For him, this extraordinary, old yet new environment represents more than just nature. "It's an ancient, mythical territory woven into Ukrainian folklore. Think of all those Cossacks galloping through valleys with forests so dense that the sun barely pierced through," he says.
That historic landscape disappeared in 1956 when the Soviet Union completed the Kahovka Dam and hydroelectric plant, flooding the entire region. What was once an ecological and cultural cradle became a reservoir, and its rich living systems were buried underwater.
Then, in 2023, the massive volume of water was used as a weapon: the Nova Kakhovka Dam on the Dnieper River, under the control of Russian forces, was blown up - Russia denies the bombing - and the vast and destructive mass of water and sediments flowed downstream, destroying villages and killing an unknown number of people. Figures regarding the death toll range from a few dozen to hundreds. Up to a million people lost access to clean water.
Two years after the disaster, the future of the reservoir is still uncertain.
Scientists say the vegetation that has developed here represents both a "return to life" for the ecosystem and the wildlife that inhabit it, as well as an unpredictable, potentially toxic "time bomb." It is a case study on the complexity of how nature responds to the vast changes brought about by humanity and what happens to ecosystems in the aftermath of a disaster.
A Desert of Mud Transformed into a Green Sea
Immediately after the bombing, the Kahovka reservoir resembled a dry mud desert with cracked mud. Now, plants grow so densely that you have to dig through the vegetation covering the embankment to see the basin.
The former arid shore is scattered with shells and husks of aquatic organisms that once lived here. Beyond it, a forest of young trees stretches to the horizon towards the occupied Zaporizhia nuclear plant.
Its size is hard to imagine: the surface area of the reservoir was 2,155 square kilometers, larger than New York City and its five boroughs combined.
The most recent report from the Ukrainian War Environmental Consequences Working Group (UWEC) confirms what satellite images, ecologists, and field researchers have begun to observe in the last two years: the ecosystem in the lower Dnieper is not only recovering but evolving: the drained reservoir now hosts dense willow and poplar vegetation and vast wetlands; the endangered sturgeons have returned to the waterways; wild boars and mammals have reappeared in the forests; and there are signs of spontaneous regeneration over a huge stretch of floodplain.
"We are witnessing the emergence of a massive natural system of floodplain forests. It's not a controlled project. It's about the land coming back to life," said Oleksii Vasiluk, co-author of a 2025 report for UWEC on the reservoir and head of the Ukrainian Nature Conservation Group.
This recovery is becoming increasingly measurable for ecologists. "Native fauna is returning to the dam-free river section and lake. Alongside a rapid expansion of native vegetation, up to 40 billion tree seeds have sprouted, potentially leading to the formation of the largest floodplain forest in Ukraine's steppe zone," confirms the report.
According to Eugene Simonov, international coordinator at Rivers without Boundaries, what is happening in Velikii Luh is not just a return of the local wetland but a rare and spontaneous reconstitution of a vast riparian ecosystem, with implications extending far beyond Ukraine.
"Before the dam was built, the Dnieper floodplain hosted huge oak forests and various types of wetlands over thousands of square kilometers, creating a mosaic of habitats rich in biodiversity for hundreds of bird species and giant fish, such as the Ukrainian sturgeon, which used to come here to spawn," explained Simonov.
This nature recovery, however, is not guaranteed, scientists emphasize.
Much of the former reservoir remains inaccessible due to ongoing bombings and mined areas. Comprehensive biological monitoring is challenging. Heavy metals and chemical contamination are becoming growing concerns for researchers. And the future of the area remains politically uncertain.
A Toxic Time Bomb
Although the forest at the bottom of the lake appears as an oasis emerging in the absence of humans, it is still marked by remnants of human activity.
Over time, the reservoir's shores have eroded. Fine dust particles have settled into a thick layer on the lakebed. At the same time, pollutants - especially heavy metals from industrial enterprises along and upstream of the lake - have seeped into the water.
"All these pollutants have been absorbed into the fine particles deposited on the water's bottom. The sediment acted like 'a huge sponge accumulated on the bottom of this reservoir. We estimate it was about 1.5 cubic kilometers of polluted sediments," said Oleksandra Shumilova, a freshwater ecologist.
When the dam was destroyed, a huge amount of potentially toxic pollutant waste leaked into the extended area. The heavy metals in them could easily contaminate water sources, soil, and be absorbed by plants.
Even in small concentrations, these can "have negative effects on vital systems of human organisms, for example, they can cause cancer, endocrine disorders, lung problems, kidney problems," says Shumilova. She compares their effects to radiation: as these toxins move up the food chain, they can concentrate, causing specific issues for larger animals and meat consumers.
"Regarding how these pollutants are transferred within the food web, it is not known. It cannot be analyzed at this time because it is dangerous to enter the area. There is no systematic research," she says.
A 2025 report, in which Shumilova collaborated and which was published in the journal Science, concluded that the pollutants represented a "toxic time bomb" and warned of significant concerns for animal trophic networks and human populations living in the area.
However, as in other environments - such as the site of the Chernobyl nuclear disaster - contamination and natural regeneration can occur simultaneously.
In the same study, scientists concluded that within five years, 80% of the ecosystem functions lost due to the presence of the dam will be restored, and the floodplain's biodiversity will significantly recover within two years.
What Will Happen Next?
The UWEC report presents this moment as a strategic turning point for Ukraine's environmental and cultural policy. If allowed to regenerate, the site could become one of the largest continuous freshwater ecosystems in Europe, rivaling even the Danube Delta in ecological importance. However, the emerging forest at Kahovka could disappear as quickly as it appeared.
"If the hydroelectric dam is rebuilt, this young forest and all the life it supports now will be lost again," warns Vasiluk.
The state energy company Ukrhydroenergo has already signaled its intention to rebuild the Kahovka hydroelectric plant. For some officials, this represents a return to "normalcy": a restoration of industrial productivity, energy security, and geopolitical control.
"Rebuilding the dam as it was before would not be a recovery, it would be an ecocide. It would destroy a young, spontaneous forest before we even have a chance to understand it," Vasiliuk emphasizes.
The decision has implications beyond Ukraine's borders. Approximately 80% of the territory affected by the reservoir collapse is located in nationally and internationally protected areas, many of which are part of Europe's Emerald Network, placing the fate of Lake Velikii Luh in a broader continental context of ecological and cultural heritage protection.
From a climate perspective, the newly formed ecosystem offers significant potential for carbon capture and storage, concludes the 2025 UWEC report.
"This is a chance we cannot afford to miss. If Ukraine chooses to protect Velikii Luh, it will not only save a landscape, but will choose to believe in its own future. Our biocultural sovereignty is at stake, and that means our nature, our identity, our independence, and a symbol of the kind of nation we want to become," says Simonov.
Along the lower Dnieper, small songbirds like the reed warbler nest in the reeds, where once the water lapped against concrete, and sturgeons deposit their eggs in shallow areas they haven't visited in 70 years. The new wetland area reflects an ancient rhythm.
"What will happen to this area? We cannot predict with full confidence at this moment, but it is true that it is recovering very rapidly," says Shumilova. "From a human perspective, it was, of course, a disaster for the people who lived there. But from a scientific point of view, it is a very rare event: how an ecosystem can be restored. It is a large-scale natural experiment. And it is still ongoing."
T.D.